OHSU -- Researchers at the Oregon Health & Science University School of Dentistry (www.ohsu.edu/sod) have found the majority of patients with self-ligating orthodontic brackets retain fewer bacteria in plaque than patients with elastomeric orthodontic brackets. The OHSU team also found that a biochemical technique measuring ATP- (adenosine triphosphate-) driven bioluminescence could be a useful chair-side tool in the rapid quantification of oral bacteria and in the assessment of oral hygiene during orthodontic treatment.